Wireless sensors are used in a variety of applications such as reading gas meters, monitoring temperatures, etc. These wireless sensors are often placed in locations where they cannot be plugged in to a wired power source and therefore must rely on battery power for long periods of time. To conserve battery power, these devices typically go in to a low power mode between measurements and communications.
Once a wireless sensor has recorded a certain amount of data, that data may be transmitted back to a central server for further processing. For example, gas meter readings may be sent to the associated gas company in order to prepare gas bills for those customers. In addition, sensor applications must allow for data collection and processing behaviors that change over time based upon changing environmental and operating conditions. For example, measurements should be taken only when they are needed, and the sensor should shut down or slow down to conserve energy when less information is needed or when other devices can take on some of the measurement taking burden. Accordingly, the central server may transmit new instructions to the wireless sensor. For example, the server may instruct the sensor to only take temperature readings once every hour instead of twice every hour.
Often, these wireless sensors communicate with the central server via an access point. An access point is a device that allows wireless devices, such as wireless sensors, to connect to a wired network, such as the Internet. However, each time the wireless sensor sends data to the central server and/or receives instructions from the central server, the wireless device must come out of low power mode and use power to perform the communications.